The present invention relates to a process for injection of refrigerated suspended particles into food products and the products resulting from such process. The present invention applies to the food industry in the field of meat products, and reveals those characteristics which are relevant for the process of preparation of said meat products suspension, to be later aggregated on larger sized meat products, as well as those characteristics which are relevant for said injection process.
The main object of the present invention is to increase the final product green weight without incurring loss of flavor, shortening of shelf life, nutritional value or texture, making feasible the incorporation of smaller size pieces to a product featuring a higher commercial value.
The term meat products is herein used meaning those products extracted from poultry, fish, cattle, pork, sheep, etc., both with and without fat, either in the shape of meat cut or shred, ground meat, frozen meat, semi-frozen meat or refrigerated meat.
The state of the art regarding the present invention can be established with the aid of several documents, among them U.S. Pat. No. 4,960,599 granted to Cozzini et al., which is herein incorporated by reference.
The systems for preparation of the suspension and for its injection in the meat products of the current state of the art may be described based on five main components:
A) Mixing silo;
B) Forced feeding reduction mill;
C) Suspension storage silo;
D) Return silo; and
E) Injection head.
Referring to FIG. 1, the function of the mixing silo (A) is to store and refrigerate the mix of brine and meat. When it reaches a temperature between −4.5° C. and −9° C., said mixture is carried to the forced feeding reduction mill (B), where it is transformed into the suspension (which is a mixture that integrates one or more liquid or oil phases with at least one solid phase). Then said suspension is carried to the suspension storage silo (C), where a heat exchanger (D) for continuous refrigeration keeps the resulting suspension temperature below 0° C. After that, the suspension is transferred, with the aid of a centrifugal pump (P), to the injection head (E), equipped with a set of injection needles (F). A conveyor (G) conveys the meat products of commercial dimensions to the injection head (E). The injection process itself takes place when a commercial dimension meat product, laid under said injection head (E), is penetrated by its set of injection needles (F). Said needles inject the suspension in multiple points of the meat product. The excess suspension generated on the injection operation is collected in the return silo (H) and sent, with the aid of a lobe pump (not shown) back to the mixing silo (A), closing the cycle.
The current state of the art presents some inconveniences.
The suspension storage silo (C) of the current state of the art systems features a single pump (P), which prevents the use of multiple injectors or injectors with multiple heads, therefore limiting the system's productivity.
Furthermore, the different values of friction and viscosity of the suspension components (meat, brine and optional additives) associated with the mechanical characteristics of the injection process cause the excess suspension collected below the injection head (E) and stored in the return silo (H) to present a different proportion between the component elements of the suspension than the suspension contained in the suspension storage silo. Usually said excess suspension presents a higher meat content than the one originally set by the forced feeding reduction mill (B) placed between the mixing silo (A) and the suspension storage silo (C). In the current state of the art systems, the return of the excess suspension from the injector to the mixing silo causes a change in the delicate balance between the suspension components, i.e. a disproportion between the brine and meat products. Said change of suspension balance in turn tends to cause a progressive yield loss in the injection process.
Another inconvenience is that the current state of the art injection systems do not allow a precise and consistent control of the injection pressure. Said injection pressure control is critical for the system's performance. If the injection pressure is too low, the suspension does not penetrate between the fibers of the meat product to be injected, thus keeping the meat product from admitting the suspension quantity originally intended for it. If the injection pressure is too high, the injection damages the meat product (sometimes even turning it to shreds) and also prevents the adequate control of the quantity of suspension aggregated to the meat product.